1. Field of the Invention
The technical scope of the invention is that of locking devices for the deployable surfaces of projectiles, such as wings, elevons or fins.
2. Description of the Related Art
It is classical to provide projectiles with stabilizing fins fired from a smooth-bore gun. During firing such fins lie along an external surface of the projectile or are inserted into radial housings. They deploy upon exiting the barrel to ensure their stabilizing function.
The stabilizing elements are generally sought to be deployed as quickly as possible to reduce the projectile's time of unstable flight, which is a source of dispersion with respect to the expected trajectory.
Patent FR-2860577 thus describes a deployment device for such fins.
Once deployed, the fins must occupy a reliable position and remain in this position. The absence of rebound is furthermore sought after since the existence of rebound delays the time at which the fins starts to become aerodynamically effective.
However, rapid deployment may well lead to the fin rebounding and there is, a priori, a certain contradiction between the requirement for the fins to be rapidly opened (a few milliseconds) and that of ensuring the reliable locking without rebound of the fins.
Moreover, the different positions of the fins constituting the tail piece cause aerodynamic imbalances which are both undesirable and impair flight accuracy.
Locking the fins is an essential function at the end of the opening phase. We note that, for the case of canards, failure to lock is catastrophic.
Different solutions to lock the fins have been imagined. Thus, FR-2860577 proposes an opening made in a block with respect to which the fin pivots, such opening receiving the end of a rod carrying the fin.
DE-19941557 and DE-19941555 describe bolts which cooperate with notches made in the fins.
The solutions associating bolts and notches are not satisfactory since there is always functional play remaining which enables angular movement of the fin with respect to its support. This results in movements or vibrations of the fins which impair firing accuracy. To this day, there are no satisfactory solutions to prevent rebounding.